Fault Tolerance Techniques facilitate systems to carry out tasks in the incidence of faults. A checkpoint is a local state of a process saved on stable storage. In a distributed system, since the processes in the system do not share memory; a global state of the system is defined as a combination of local states, one from each process. In case of a fault in distributed systems, checkpointing enables the execution of a program to be resumed from a previous consistent global state rather than resuming the execution from the commencement. In this way, the sum of constructive processing vanished because of the fault is appreciably reduced. In this paper, we talk about various issues related to the checkpointing for distributed systems and mobile computing environments. We also confer
various types of checkpointing: coordinated checkpointing, asynchronous checkpointing, communication induced
checkpointing and message logging based checkpointing. We also present a survey of some checkpointing algorithms for distributed systems.
This document discusses synchronization in distributed systems and various algorithms for achieving mutual exclusion. It covers centralized, distributed, and token ring algorithms for mutual exclusion. The centralized algorithm uses a coordinator but has a single point of failure. Distributed algorithms overcome this but require more messages. The token ring algorithm passes a token between processes but can lose the token if a process crashes. In comparing the algorithms, the document examines their message requirements, delay before entry, and potential problems.
The document discusses various techniques for resource management in distributed systems. It describes approaches like task assignment, load balancing, and load sharing. It also covers desirable features of scheduling algorithms and discusses techniques like task assignment in detail with an example. Furthermore, it discusses concepts like load balancing approaches, task assignment, location policies, state information exchange policies, and priority assignment policies.
The document discusses various algorithms for achieving distributed mutual exclusion and process synchronization in distributed systems. It covers centralized, token ring, Ricart-Agrawala, Lamport, and decentralized algorithms. It also discusses election algorithms for selecting a coordinator process, including the Bully algorithm. The key techniques discussed are using logical clocks, message passing, and quorums to achieve mutual exclusion without a single point of failure.
This document discusses process management in distributed systems. It describes how distributed operating systems aim to make the best use of processing resources across an entire system by sharing processors among all processes. Key concepts discussed include processor allocation, process migration, and threads. Process migration involves transferring a running process from one machine to another to achieve goals like load balancing and fault tolerance. The challenges and mechanisms of freezing, transferring, and restarting a migrating process's address space and forwarding messages are also covered.
This document discusses resource management techniques in distributed systems. It covers three main scheduling techniques: task assignment approach, load balancing approach, and load sharing approach. It also outlines desirable features of good global scheduling algorithms such as having no a priori knowledge about processes, being dynamic in nature, having quick decision-making capability, balancing system performance and scheduling overhead, stability, scalability, fault tolerance, and fairness of service. Finally, it discusses policies for load estimation, process transfer, state information exchange, location, priority assignment, and migration limiting that distributed load balancing algorithms employ.
Process Migration in Heterogeneous Systemsijsrd.com
This document discusses process migration in heterogeneous distributed systems. Process migration involves transferring the entire state of a process from one computer to another so execution can continue. In heterogeneous systems, data must be translated between the source and destination computer formats. The document proposes using an external data representation standard to reduce the complexity of the translation software needed. It also describes challenges in migrating processes that use floating point numbers or signed values and how these can be addressed through the external data representation. The advantages of process migration for load balancing and improving system reliability and performance are also summarized.
This document provides an introduction to distributed systems. It discusses why distributed systems are developed, defines what a distributed system is, and provides examples. It then compares different types of distributed systems and networked operating systems. The rest of the document outlines various concepts, issues, and algorithms related to distributed systems, including advantages and disadvantages over centralized systems, software concepts, mutual exclusion, synchronization, and clock synchronization.
This document discusses synchronization in distributed systems and various algorithms for achieving mutual exclusion. It covers centralized, distributed, and token ring algorithms for mutual exclusion. The centralized algorithm uses a coordinator but has a single point of failure. Distributed algorithms overcome this but require more messages. The token ring algorithm passes a token between processes but can lose the token if a process crashes. In comparing the algorithms, the document examines their message requirements, delay before entry, and potential problems.
The document discusses various techniques for resource management in distributed systems. It describes approaches like task assignment, load balancing, and load sharing. It also covers desirable features of scheduling algorithms and discusses techniques like task assignment in detail with an example. Furthermore, it discusses concepts like load balancing approaches, task assignment, location policies, state information exchange policies, and priority assignment policies.
The document discusses various algorithms for achieving distributed mutual exclusion and process synchronization in distributed systems. It covers centralized, token ring, Ricart-Agrawala, Lamport, and decentralized algorithms. It also discusses election algorithms for selecting a coordinator process, including the Bully algorithm. The key techniques discussed are using logical clocks, message passing, and quorums to achieve mutual exclusion without a single point of failure.
This document discusses process management in distributed systems. It describes how distributed operating systems aim to make the best use of processing resources across an entire system by sharing processors among all processes. Key concepts discussed include processor allocation, process migration, and threads. Process migration involves transferring a running process from one machine to another to achieve goals like load balancing and fault tolerance. The challenges and mechanisms of freezing, transferring, and restarting a migrating process's address space and forwarding messages are also covered.
This document discusses resource management techniques in distributed systems. It covers three main scheduling techniques: task assignment approach, load balancing approach, and load sharing approach. It also outlines desirable features of good global scheduling algorithms such as having no a priori knowledge about processes, being dynamic in nature, having quick decision-making capability, balancing system performance and scheduling overhead, stability, scalability, fault tolerance, and fairness of service. Finally, it discusses policies for load estimation, process transfer, state information exchange, location, priority assignment, and migration limiting that distributed load balancing algorithms employ.
Process Migration in Heterogeneous Systemsijsrd.com
This document discusses process migration in heterogeneous distributed systems. Process migration involves transferring the entire state of a process from one computer to another so execution can continue. In heterogeneous systems, data must be translated between the source and destination computer formats. The document proposes using an external data representation standard to reduce the complexity of the translation software needed. It also describes challenges in migrating processes that use floating point numbers or signed values and how these can be addressed through the external data representation. The advantages of process migration for load balancing and improving system reliability and performance are also summarized.
This document provides an introduction to distributed systems. It discusses why distributed systems are developed, defines what a distributed system is, and provides examples. It then compares different types of distributed systems and networked operating systems. The rest of the document outlines various concepts, issues, and algorithms related to distributed systems, including advantages and disadvantages over centralized systems, software concepts, mutual exclusion, synchronization, and clock synchronization.
4.1Introduction
- Potential Threats and Attacks on Computer System
- Confinement Problems
- Design Issues in Building Secure Distributed Systems
4.2 Cryptography
- Symmetric Cryptosystem Algorithm: DES
- Asymmetric Cryptosystem
4.3 Secure Channels
- Authentication
- Message Integrity and Confidentiality
- Secure Group Communication
4.4 Access Control
- General Issues
- Firewalls
- Secure Mobile Code
4.5 Security Management
- Key Management
- Issues in Key Distribution
- Secure Group Management
- Authorization Management
Introduction: What is clock synchronization?
The challenges of clock synchronization.
Basic Concepts: Software and hardware clocks. Basic clock synchronization algorithm
Algorithms: Deep dive into landmark papers
NTP: Internet scale time synchronization
Distributed Middleware Reliability & Fault Tolerance Support in System SHarini Sirisena
The document discusses techniques for building reliable large-scale distributed systems. It describes how System S achieves reliability through two key building blocks - an inter-component communication infrastructure that handles failures and remote procedure calls, and a data storage mechanism. System S uses CORBA for communication and IBM DB2 for data storage. It also discusses how System S handles component failures through retrying operations, managing component state, and ensuring idempotent and non-idempotent operations are executed correctly.
Allocation of processors to processes in Distributed Systems. Strategies or algorithms for processor allocation. Design and Implementation Issues of Strategies.
AN ALTERNATE APPROACH TO RESOURCE ALLOCATION STRATEGY USING NETWORK METRICSIN...ijgca
Monitoring in a grid environment involves the analysis of all resource metrics and network metrics. Monitoring the resource metrics helps the grid middle ware to decide which job to be
submitted to which resource. Decision for submitting a job will be better along with the consideration of the network metrics. Tuning of the network metrics is also made if the performance degrades.
This document proposes an application-level checkpoint-based approach for fault tolerance in distributed systems. The system uses coordinated checkpointing and systematic process logging to monitor nodes. If a node fails, its state can be reconstructed from checkpoint information. The system is implemented for a distributed multiple sequence alignment application using genetic algorithms. Checkpoints are taken locally at each worker node and globally by the head node to monitor node status and failures.
Integrating fault tolerant scheme with feedback control scheduling algorithm ...ijics
In order to provide Quality of Service (QoS) in open and unpredictable environment, Feedback based
Control Scheduling Algorithm (FCSA) is designed to keep the processor utilization at the scheduling
utilization bound. FCSA controls CPU utilization by assigning task periods that optimize overall control
performance, meeting deadlines even if the task execution time is unpredictable and through performance
control feedback loop. Current FCSA doesn’t ensure Fault Tolerance (FT) while providing QoS in terms of
CPU utilization and resource management. In order to assure that tasks should meet their deadlines even
in the presence of faults, a FT scheme has to be integrated at control scheduling co-design level. This paper
presents a novel approach on integrating FT scheme with FCSA for real time embedded systems. This
procedure is especially important for control scheduling co-design of embedded systems.
Fault tolerance is important for distributed systems to continue functioning in the event of partial failures. There are several phases to achieving fault tolerance: fault detection, diagnosis, evidence generation, assessment, and recovery. Common techniques include replication, where multiple copies of data are stored at different sites to increase availability if one site fails, and check pointing, where a system's state is periodically saved to stable storage so the system can be restored to a previous consistent state if a failure occurs. Both techniques have limitations around managing consistency with replication and overhead from checkpointing communications and storage requirements.
Agreement Protocols, Distributed Resource Management: Issues in distributed File Systems, Mechanism for building distributed file systems, Design issues in Distributed Shared Memory, Algorithm for Implementation of Distributed Shared Memory.
The document discusses securing query processing in cloud computing environments. It identifies three key requirements for secure query processing: 1) authenticating users and machines, 2) securing data transfer across machines, and 3) ensuring integrity of query results. The document also analyzes existing and proposed systems for wireless multi-hop networks, including analyzing performance under different conditions.
Resource Allocation using Virtual Machine Migration: A Surveyidescitation
As virtualization is proving to be dominant in
enterprise and organizational networks there is a need for
operators and administrators to pay more attention to live
migration of virtual machines (VMs) with the main objective
of workload balancing, monitoring, fault management, low-
level system maintenance and good performance with minimal
service downtimes. It is also a crucial aspect of cloud computing
that offers strategies to implement the dynamic allocation of
resources. Virtualization also enables virtual machine
migration to eliminate hotspots in data centers .However the
security associated with VMs live migration has not received
thorough analysis. Further, the negative impact on service
levels of running applications is likely to occur during the
live VM migration hence a better understanding of its
implications on the system performance is highly required.
In this survey we explore the security issues involved in live
migration of VMs and demonstrate the importance of security
during the migration process. A model which demonstrates
the cost incurred in reconfiguring a cloud-based environment
in response to the workload variations is studied. It is also
proved that migration cost is acceptable but should not be
neglected, particularly in systems where service availability
and response times are imposed by stringent Service Level
Agreements (SLAs). A system that provides automation of
monitoring and detection of hotspots and determination of
the new mapping of physical to virtual resources and finally
initiates the required migrations based on its observations is
also studied. These are experimented using Xen Virtual
Machine Manager. Migration based resource Managers for
virtualized environments are presented by comparing and
discussing several types of underlying algorithms from
algorithmistic issues point of view.
Communication And Synchronization In Distributed Systemsguest61205606
This document discusses various topics related to communication and synchronization in distributed systems. It covers concepts like communication protocols, remote procedure calls, client-server and peer-to-peer models, blocking vs non-blocking communication, reliability, group communication, message ordering, and synchronization techniques including clock synchronization algorithms, mutual exclusion algorithms, and atomic transactions.
1. Distributed transaction managers ensure transactions have ACID properties through implementing the 2-phase commit protocol for reliability, 2-phase locking for concurrency control, and timeouts for deadlock detection on top of local transaction managers.
2. The 2-phase commit protocol guarantees subtransactions of the same transaction will all commit or abort despite failures, while 2-phase locking requires subtransactions acquire locks in a growing phase and release in a shrinking phase.
3. Timeouts are used to detect and abort transactions potentially experiencing a distributed deadlock.
Distributed systems use multiple autonomous computers that communicate via messages to improve processing throughput, allow for CPU specialization, and provide fault tolerance. Faults in distributed systems can include data corruption, hanging processes, misleading return values, hardware/software/network outages, and resource overcommitment. To provide fault tolerance, processes are replicated across multiple computers so the system can continue functioning even if some processes fail. There are different types of faults like crash faults, omission faults, and Byzantine faults. Recovery from failures can use backward or forward recovery approaches.
CHECKPOINTING WITH MINIMAL RECOVERY IN ADHOCNET BASED TMRijujournal
The checkpointing algorithm described in the document utilizes Triple Modular Redundancy (TMR) in a wireless ad hoc network. It proposes a distributed checkpointing and recovery protocol that eliminates unnecessary checkpoints and only recovers dependent processes. Each process tracks message dependencies during execution. When a checkpoint is initiated, processes exchange status information detailing messages sent and received. A process only checkpoints after receiving any expected messages, ensuring consistency. If a process fails, only dependent processes recover by rolling back to their last checkpoint, minimizing recovery overhead.
The document discusses faults in distributed systems, including different types of faults (transient, intermittent, permanent), fault avoidance, fault removal, and fault tolerance. It also discusses achieving fault tolerance through redundancy, with the goal of avoiding single points of failure. The remainder of the document outlines the specifications and design of a fault-tolerant distributed routing simulator, including front-end and back-end modules, class dependencies, and testing procedures.
Este documento describe los archivos secuenciales indexados, los cuales organizan registros en una secuencia basada en un campo clave e incluyen un índice para soportar accesos aleatorios y un archivo de desbordamiento. También proporciona un enlace a un código de ejemplo en C++.
The Concept of Authenticity in Philosophy of Sartre and Implications for Usin...Eswar Publications
The aim of this paper is explaining authenticity in Sartre philosophy and it’s relation to internet as an educational technology. Initially, using deceptive and analytic method, the authenticity has been explained in Sartre philosophy. Sartre. He believed that authenticity mean being honest to yourself, having freedom, take responsibility of freedom and respect other’s freedom. In analyzing these conceptions in relation to internet, we can say internet enhances ability of choosing and freedom. On the other hand because of lacing face to face
communication and being anonymous on the internet, it will result to decreasing responsibility and commitment. Existence anguish that is believed to be a positive quality in Sartre’s view, can motivate thought and action.
4.1Introduction
- Potential Threats and Attacks on Computer System
- Confinement Problems
- Design Issues in Building Secure Distributed Systems
4.2 Cryptography
- Symmetric Cryptosystem Algorithm: DES
- Asymmetric Cryptosystem
4.3 Secure Channels
- Authentication
- Message Integrity and Confidentiality
- Secure Group Communication
4.4 Access Control
- General Issues
- Firewalls
- Secure Mobile Code
4.5 Security Management
- Key Management
- Issues in Key Distribution
- Secure Group Management
- Authorization Management
Introduction: What is clock synchronization?
The challenges of clock synchronization.
Basic Concepts: Software and hardware clocks. Basic clock synchronization algorithm
Algorithms: Deep dive into landmark papers
NTP: Internet scale time synchronization
Distributed Middleware Reliability & Fault Tolerance Support in System SHarini Sirisena
The document discusses techniques for building reliable large-scale distributed systems. It describes how System S achieves reliability through two key building blocks - an inter-component communication infrastructure that handles failures and remote procedure calls, and a data storage mechanism. System S uses CORBA for communication and IBM DB2 for data storage. It also discusses how System S handles component failures through retrying operations, managing component state, and ensuring idempotent and non-idempotent operations are executed correctly.
Allocation of processors to processes in Distributed Systems. Strategies or algorithms for processor allocation. Design and Implementation Issues of Strategies.
AN ALTERNATE APPROACH TO RESOURCE ALLOCATION STRATEGY USING NETWORK METRICSIN...ijgca
Monitoring in a grid environment involves the analysis of all resource metrics and network metrics. Monitoring the resource metrics helps the grid middle ware to decide which job to be
submitted to which resource. Decision for submitting a job will be better along with the consideration of the network metrics. Tuning of the network metrics is also made if the performance degrades.
This document proposes an application-level checkpoint-based approach for fault tolerance in distributed systems. The system uses coordinated checkpointing and systematic process logging to monitor nodes. If a node fails, its state can be reconstructed from checkpoint information. The system is implemented for a distributed multiple sequence alignment application using genetic algorithms. Checkpoints are taken locally at each worker node and globally by the head node to monitor node status and failures.
Integrating fault tolerant scheme with feedback control scheduling algorithm ...ijics
In order to provide Quality of Service (QoS) in open and unpredictable environment, Feedback based
Control Scheduling Algorithm (FCSA) is designed to keep the processor utilization at the scheduling
utilization bound. FCSA controls CPU utilization by assigning task periods that optimize overall control
performance, meeting deadlines even if the task execution time is unpredictable and through performance
control feedback loop. Current FCSA doesn’t ensure Fault Tolerance (FT) while providing QoS in terms of
CPU utilization and resource management. In order to assure that tasks should meet their deadlines even
in the presence of faults, a FT scheme has to be integrated at control scheduling co-design level. This paper
presents a novel approach on integrating FT scheme with FCSA for real time embedded systems. This
procedure is especially important for control scheduling co-design of embedded systems.
Fault tolerance is important for distributed systems to continue functioning in the event of partial failures. There are several phases to achieving fault tolerance: fault detection, diagnosis, evidence generation, assessment, and recovery. Common techniques include replication, where multiple copies of data are stored at different sites to increase availability if one site fails, and check pointing, where a system's state is periodically saved to stable storage so the system can be restored to a previous consistent state if a failure occurs. Both techniques have limitations around managing consistency with replication and overhead from checkpointing communications and storage requirements.
Agreement Protocols, Distributed Resource Management: Issues in distributed File Systems, Mechanism for building distributed file systems, Design issues in Distributed Shared Memory, Algorithm for Implementation of Distributed Shared Memory.
The document discusses securing query processing in cloud computing environments. It identifies three key requirements for secure query processing: 1) authenticating users and machines, 2) securing data transfer across machines, and 3) ensuring integrity of query results. The document also analyzes existing and proposed systems for wireless multi-hop networks, including analyzing performance under different conditions.
Resource Allocation using Virtual Machine Migration: A Surveyidescitation
As virtualization is proving to be dominant in
enterprise and organizational networks there is a need for
operators and administrators to pay more attention to live
migration of virtual machines (VMs) with the main objective
of workload balancing, monitoring, fault management, low-
level system maintenance and good performance with minimal
service downtimes. It is also a crucial aspect of cloud computing
that offers strategies to implement the dynamic allocation of
resources. Virtualization also enables virtual machine
migration to eliminate hotspots in data centers .However the
security associated with VMs live migration has not received
thorough analysis. Further, the negative impact on service
levels of running applications is likely to occur during the
live VM migration hence a better understanding of its
implications on the system performance is highly required.
In this survey we explore the security issues involved in live
migration of VMs and demonstrate the importance of security
during the migration process. A model which demonstrates
the cost incurred in reconfiguring a cloud-based environment
in response to the workload variations is studied. It is also
proved that migration cost is acceptable but should not be
neglected, particularly in systems where service availability
and response times are imposed by stringent Service Level
Agreements (SLAs). A system that provides automation of
monitoring and detection of hotspots and determination of
the new mapping of physical to virtual resources and finally
initiates the required migrations based on its observations is
also studied. These are experimented using Xen Virtual
Machine Manager. Migration based resource Managers for
virtualized environments are presented by comparing and
discussing several types of underlying algorithms from
algorithmistic issues point of view.
Communication And Synchronization In Distributed Systemsguest61205606
This document discusses various topics related to communication and synchronization in distributed systems. It covers concepts like communication protocols, remote procedure calls, client-server and peer-to-peer models, blocking vs non-blocking communication, reliability, group communication, message ordering, and synchronization techniques including clock synchronization algorithms, mutual exclusion algorithms, and atomic transactions.
1. Distributed transaction managers ensure transactions have ACID properties through implementing the 2-phase commit protocol for reliability, 2-phase locking for concurrency control, and timeouts for deadlock detection on top of local transaction managers.
2. The 2-phase commit protocol guarantees subtransactions of the same transaction will all commit or abort despite failures, while 2-phase locking requires subtransactions acquire locks in a growing phase and release in a shrinking phase.
3. Timeouts are used to detect and abort transactions potentially experiencing a distributed deadlock.
Distributed systems use multiple autonomous computers that communicate via messages to improve processing throughput, allow for CPU specialization, and provide fault tolerance. Faults in distributed systems can include data corruption, hanging processes, misleading return values, hardware/software/network outages, and resource overcommitment. To provide fault tolerance, processes are replicated across multiple computers so the system can continue functioning even if some processes fail. There are different types of faults like crash faults, omission faults, and Byzantine faults. Recovery from failures can use backward or forward recovery approaches.
CHECKPOINTING WITH MINIMAL RECOVERY IN ADHOCNET BASED TMRijujournal
The checkpointing algorithm described in the document utilizes Triple Modular Redundancy (TMR) in a wireless ad hoc network. It proposes a distributed checkpointing and recovery protocol that eliminates unnecessary checkpoints and only recovers dependent processes. Each process tracks message dependencies during execution. When a checkpoint is initiated, processes exchange status information detailing messages sent and received. A process only checkpoints after receiving any expected messages, ensuring consistency. If a process fails, only dependent processes recover by rolling back to their last checkpoint, minimizing recovery overhead.
The document discusses faults in distributed systems, including different types of faults (transient, intermittent, permanent), fault avoidance, fault removal, and fault tolerance. It also discusses achieving fault tolerance through redundancy, with the goal of avoiding single points of failure. The remainder of the document outlines the specifications and design of a fault-tolerant distributed routing simulator, including front-end and back-end modules, class dependencies, and testing procedures.
Este documento describe los archivos secuenciales indexados, los cuales organizan registros en una secuencia basada en un campo clave e incluyen un índice para soportar accesos aleatorios y un archivo de desbordamiento. También proporciona un enlace a un código de ejemplo en C++.
The Concept of Authenticity in Philosophy of Sartre and Implications for Usin...Eswar Publications
The aim of this paper is explaining authenticity in Sartre philosophy and it’s relation to internet as an educational technology. Initially, using deceptive and analytic method, the authenticity has been explained in Sartre philosophy. Sartre. He believed that authenticity mean being honest to yourself, having freedom, take responsibility of freedom and respect other’s freedom. In analyzing these conceptions in relation to internet, we can say internet enhances ability of choosing and freedom. On the other hand because of lacing face to face
communication and being anonymous on the internet, it will result to decreasing responsibility and commitment. Existence anguish that is believed to be a positive quality in Sartre’s view, can motivate thought and action.
A Survey of Various Fault Tolerance Checkpointing Algorithms in Distributed S...Eswar Publications
A distributed system is a collection of independent entities that cooperate to solve a problem that cannot be individually solved. Checkpoint is defined as a fault tolerant technique. It is a save state of a process during the failure-free execution, enabling it to restart from this checkpointed state upon a failure to reduce the amount of lost work instead of repeating the computation from beginning. The process of restoring form previous checkpointed state is known as rollback recovery. A checkpoint can be saved on either the stable storage or the
volatile storage depending on the failure scenarios to be tolerated. Checkpointing is major challenge in mobile ad
hoc network. The mobile ad hoc network architecture is one consisting of a set of self configure mobile hosts(MH) capable of communicating with each other without the assistance of base stations, some of processes running on mobile host. The main issues of this environment are insufficient power and limited storage capacity. This paper surveys the algorithms which have been reported in the literature for checkpointing in distributed systems as well as Mobile Distributed systems.
Traditional interpreted data-flow analysis is executed on whole plans; however, such whole-program psychoanalysis is not
executable for large or uncompleted plans. We suggest fragment data-flow analysis as a substitute approach which
calculates data-flow information for a particular program fragment. The psychoanalysis is parameterized by the extra
information available about the rest of the program. We depict two frameworks for interracial flow-sensitive fragment
psychoanalysis, the relationship amongst fragment psychoanalysis and whole-program analysis, and the necessities ensuring fragment analysis safety and feasibility. We suggest an application of fragment analysis as a second analysis phase after a cheap flow-insensitive whole-program analysis, in order to obtain better data for important program fragments. We also depict the design of two fragment analyses derived from an already existing whole-program flow- and context-sensitive pointer alias analysis for Computer program and present empirical rating of their cost and precision. Our experiments show evidence of dramatic improves precision gettable at a practical cost.
Este documento presenta el calendario tributario para Colombia en 2012, incluyendo fechas límite para retención en la fuente, declaración y pago de impuestos sobre la renta e IVA para personas naturales y jurídicas, así como fechas para la declaración y pago de otros impuestos como al patrimonio y precios de transferencia. También incluye el calendario para la declaración del gravamen a los movimientos financieros.
This certificate of completion was granted to Tamara Mitchell for successfully completing a course on Applying the QM Rubric (APPQMR) on June 7, 2016. The course was facilitated by Rachel Gonzalez through the quality matters program website at www.qmprogram.org.
Forestalling Meticulous Jam Attacks Using Packet-Hiding TechniquesEswar Publications
The open nature of the wireless medium leaves it liable to intentional interference attacks, generally said as jam.
This intentional interference with wireless transmissions is used as a launch pad for mounting Denial-of-Service attacks on wireless networks. Typically, jam has been self-addressed beneath associate external threat model.
However, adversaries with internal information of protocol specifications and network secrets will launch loweffort
jam attacks that are troublesome to notice and counter. during this work, we have a tendency to address the matter of jamming attacks in wireless networks. In these attacks, the resister is active just for a brief amount of your time, by selection targeting messages of high importance. In our work two offender nodes (node that creates jamming) and introduce one new node i.e sender node. The new node(jammer node) is at intervals the twenty five nodes. Victimization that new sender node we have to eliminate the offender nodes absolutely. We have a tendency to conclude that however jam happens within the network and approach of elimination of the offender nodes
victimization new sender node. We propose mistrial approach for avoid flooding packets in jammer network. We conclude the performance between the mistrial and damping approach for avoid jamming packets We have a tendency to illustrate the benefits of {selective jam|spot-jamming|jamming|electronic jamming|jam} in terms of network performance degradation and resister effort by to beat the sender in network with the assistance of recent jamming node. We illustrate the benefits of jam|spot-jamming|jamming|electronic-jamming|jam} in terms of network performance degradation and human effort by to beat the sender in network with the assistance of recent
jamming node.
Este documento describe diferentes tipos de patrones de medición, incluyendo patrones internacionales, primarios, secundarios y de trabajo. Explica qué es un patrón de medición y provee ejemplos como el metro y la yarda. También describe patrones específicos como bloques patrón, barras de extremo, patrones de diámetro y patrones angulares.
Contains information about a career development and explains the steps in the career development process. The employees' and employers' roles in career development process are discussed.
Career planning, development, succession planningRohini B. Agre
The document discusses career planning, development, and succession planning. It outlines the steps in career planning which include preparing skills inventories, developing career paths, training, and counseling. Succession planning ensures leadership continuity, retains intellectual capital, and encourages advancement. The steps in succession planning are preparing a management inventory, performance appraisals, retaining personnel, and staffing plans. Management development programs provide scientific training to enrich knowledge and skills. Organization development is a planned, organization-wide effort to increase effectiveness through behavioral interventions in processes.
Este documento describe un proyecto para abrir un colegio privado en Bargas, Toledo. Se analizan los costes de mantener una clase, incluyendo el salario de un profesor (18,745.72€ al año) y los gastos de materiales e instalaciones (12,099.07€ al año). El coste total para cada alumno sería de 114.23€ al mes. El colegio ofrecería clases de 9 a 14 horas y actividades extracurriculares por las tardes de lunes a viernes para reforzar los aprendiz
Checkpointing and Rollback Recovery Algorithms for Fault Tolerance in MANETs:...Eswar Publications
This document summarizes and reviews various checkpointing and rollback recovery algorithms that have been proposed to provide fault tolerance in mobile ad hoc networks (MANETs). It begins with background information on MANETs and checkpointing. Checkpointing techniques take snapshots of process states and store them to allow recovery from failures without restarting from the beginning. The document then describes different types of checkpointing, including uncoordinated, coordinated, communication-induced, and hybrid approaches. Several specific algorithms for MANETs checkpointing are then analyzed, including flooding-based, concurrent checkpointing, cluster-based, and mobility-aware approaches. The document concludes by stating that checkpointing presents challenges for MANETs due to their dynamic topology and limited
1. The document presents a failure recovery scheme for mobile computing systems based on checkpointing and handoff count. It proposes taking checkpoints when the handoff count exceeds a threshold or the distance between mobile support stations exceeds a threshold.
2. The scheme aims to optimize both failure-free operation costs and failure recovery costs. Checkpoints are taken to minimize the amount of work lost after failures while limiting overhead during normal operation.
3. By delimiting the number of mobile support stations and distance from which recovery information needs to be collected, the proposed scheme aims to reduce recovery time and costs. Taking checkpoints based on handoff count and distance thresholds helps organize recovery information to facilitate efficient failure recovery.
1. The document presents a failure recovery scheme for mobile computing systems based on checkpointing and handoff count. It proposes taking checkpoints when the handoff count exceeds a threshold or the distance between mobile support stations exceeds a threshold.
2. Upon failure, recovery information is collected from the mobile support stations where checkpoints are stored. The number of support stations and distance between them affects recovery time and cost.
3. The proposed scheme aims to optimize failure recovery by limiting the number of support stations and distance based on handoff count thresholds. Checkpoints are initiated to minimize scattered recovery information across multiple distant support stations.
A fault tolerant tokenbased atomic broadcast algorithm relying on responsive ...Neelamani Samal
This document summarizes a fault tolerant token-based atomic broadcast algorithm that relies on an unreliable failure detector and satisfies the responsive property. The algorithm aims to tolerate processor-level failures in a distributed system. It divides a job into tasks, uses a token to control access to shared resources, and monitors task execution times. If a task does not respond within the timeout period, it is declared faulty and removed from the ready queue. The algorithm was implemented on a multi-core processor to simulate fault tolerance capabilities in a distributed system within a specified time interval.
CHECKPOINTING WITH MINIMAL RECOVERY IN ADHOCNET BASED TMRijujournal
The checkpointing algorithm described in the document takes a distributed approach where processes coordinate to take consistent checkpoints. Each process tracks the number of messages sent to and received from other processes during a checkpoint interval. When a checkpoint is initiated, this status information is shared. Processes only checkpoint after verifying that the number of sent and received messages match for all other processes, ensuring consistency. By tracking dependencies, only processes dependent on a failed process need rollback for recovery. This minimizes unnecessary rollbacks compared to naive approaches.
CHECKPOINTING WITH MINIMAL RECOVERY IN ADHOCNET BASED TMRijujournal
This paper describes two-fold approach towards utilizing Triple Modular Redundancy (TMR) in Wireless
Adhoc Network (AdocNet). A distributed checkpointing and recovery protocol is proposed. The protocol
eliminates useless checkpoints and helps in selecting only dependent processes in the concerned
checkpointing interval, to recover. A process starts recovery from its last checkpoint only if it finds that it is
dependent (directly or indirectly) on the faulty process. The recovery protocol also prevents the occurrence
of missing or orphan messages. In AdocNet, a set of three nodes (connected to each other) is considered to
form a TMR set, being designated as main, primary and secondary. A main node in one set may serve as
primary or secondary in another. Computation is not triplicated, but checkpoint by main is duplicated in its
primary so that primary can continue if main fails. Checkpoint by primary is then duplicated in secondary
if primary fails too.
A comparative analysis of minimum process coordinated checkpointing algorithm...IAEME Publication
This document summarizes and compares several minimum-process coordinated checkpointing algorithms for mobile distributed systems. It begins with background on checkpointing techniques in distributed systems and issues specific to mobile distributed systems. It then describes five minimum-process coordinated checkpointing protocols: the Cao and Singhal algorithm, the Kumar and Kumar algorithm, the Silva and Silva algorithm, Koo-Toueg's algorithm, and the Coa and Singhal blocking algorithm. For each algorithm, it provides a brief overview of the approach and key aspects. The document aims to provide a comparative analysis of existing minimum-process checkpointing protocols for mobile distributed systems.
A comparative analysis of minimum process coordinatediaemedu
This document summarizes and compares several minimum-process coordinated checkpointing algorithms for mobile distributed systems. It begins with background on checkpointing techniques in distributed systems and issues specific to mobile distributed systems. It then describes five minimum-process coordinated checkpointing protocols: the Cao and Singhal algorithm, the Kumar and Kumar algorithm, the Silva and Silva algorithm, Koo-Toueg's algorithm, and the Coa and Singhal blocking algorithm. For each algorithm, it provides a brief overview of the approach and key aspects. The document aims to provide a comparative analysis of existing minimum-process checkpointing protocols for mobile distributed systems.
A comparative analysis of minimum process coordinatediaemedu
This document summarizes checkpointing algorithms for mobile distributed systems. It discusses minimum-process coordinated checkpointing as a preferred approach. It describes asynchronous and synchronous checkpointing, and categorizes the latter into minimum-process and all-process algorithms. Minimum-process algorithms only require interacting processes to checkpoint, while all-process checkpoints all processes. Blocking and non-blocking variants are also discussed. The document focuses on challenges of mobility for traditional distributed system checkpointing algorithms.
A comparative analysis of minimum process coordinated checkpointingiaemedu
This document summarizes and compares several minimum-process coordinated checkpointing algorithms for mobile distributed systems. It begins with background on checkpointing techniques in distributed systems and issues specific to mobile distributed systems. It then describes five minimum-process coordinated checkpointing protocols: the Cao and Singhal algorithm, the Kumar and Kumar algorithm, the Silva and Silva algorithm, Koo-Toueg's algorithm, and the Coa and Singhal blocking algorithm. For each algorithm, it provides a brief overview of the approach and key aspects. The document aims to provide a comparative analysis of existing minimum-process checkpointing protocols for mobile distributed systems.
This is a presentation for Chapter 7 Distributed system management
Book: DISTRIBUTED COMPUTING , Sunita Mahajan & Seema Shah
Prepared by Students of Computer Science, Ain Shams University - Cairo - Egypt
Hierarchical Non-blocking Coordinated Checkpointing Algorithms for Mobile Dis...CSCJournals
Mobile system typically uses wireless communication which is based on electromagnetic waves and utilizes a shared broadcast medium. This has made possible creating a mobile distributed computing environment and has brought us several new challenges in distributed protocol design. So many issues such as range of transmission, limited power supply due to battery capacity and mobility of processes. These new issue makes traditional recovery algorithm unsuitable. In this paper, we propose hierarchical non blocking coordinated checkpointing algorithms suitable for mobile distributed computing. The algorithm is non-blocking, requires minimum message logging, has minimum stable storage requirement and produce a consistent set of checkpoints. This algorithm requires minimum number of processes to take checkpoint.
This document presents a two-phase algorithm to establish consistent checkpoints for recovery in a multi-process distributed system. In phase one, a coordinator process assigns tasks to cohort processes and divides its weight evenly among them. When a cohort completes its task, it returns its weight to the coordinator and takes a tentative checkpoint. Once the coordinator's weight reaches its initial value, no messages are in transit and a consistent global state is reached. In phase two, the coordinator tells all processes to finalize their checkpoints for recovery from failures. The algorithm aims to minimize the number of additional processes that must rollback when one process fails.
This document discusses different approaches to resource management in distributed systems, including task assignment, load balancing, and load sharing. The task assignment approach views each process as a collection of tasks and schedules the tasks across nodes to improve performance. The load balancing approach distributes processes across nodes to equalize workloads. The load sharing approach aims to ensure no nodes are idle while processes wait. Effective resource management requires algorithms that make quick decisions with minimal overhead while optimizing resource usage and response times.
Formal Verification of Distributed Checkpointing Using Event-Bijcsit
The document describes formal verification of checkpointing in a distributed database system using Event-B. It presents an Event-B model that specifies the checkpointing process. Key aspects of the model include assigning timestamps to messages and transactions, marking transactions as before or after checkpoint based on their timestamps, and computing a global checkpoint number. The model is verified using the Rodin tool to ensure the checkpointing process satisfies correctness properties.
Fault recovery tactics in software systems include:
- Voting with redundant components to detect and correct faults. Diversity uses different software/hardware to detect algorithm faults.
- Active redundancy keeps redundant components synchronized in real-time, allowing recovery in milliseconds by switching to backups.
- Passive redundancy uses a primary component with backup components that are periodically resynchronized, allowing recovery in seconds.
- Using spare components requires reconfiguring software and state on the spare, increasing recovery time to minutes.
- Other tactics for recovering failed components include running them in shadow mode, resynchronizing their state, and rolling back to checkpoints.
Behavior modeling of soft real time system using stereotyped extension mechan...eSAT Publishing House
This document discusses modeling the behavior of soft real-time systems using stereotyped extensions in UML use case modeling. It proposes a new UML use case stereotyping metamodel that adds 12 stereotypes categorized as basic, intermediate, and advanced. These stereotypes can be used to model the static behavior of soft real-time systems like online transaction processing systems, using the example of a credit card processing system. The document also discusses modeling four scenarios for the credit card processing system: card/PIN issuance, merchant account management, acquiring bank processing, and payment gateway management.
Cooperating processes work together to complete tasks by sharing resources like CPU, memory, and I/O devices. They communicate using shared memory or message passing. Shared memory allows faster communication by sharing an address space, while message passing is slower but can be used across devices. The critical section problem occurs when multiple processes access shared resources simultaneously, potentially corrupting data. Solutions ensure mutual exclusion so only one process is in the critical section at a time through techniques like disabling interrupts or using lock variables.
Fault tolerance is the dynamic method that’s used to keep the interconnected systems together, sustain reliability, and availability in distributed systems.
Similar to Review of Some Checkpointing Schemes for Distributed and Mobile Computing Environments (20)
Content-Based Image Retrieval (CBIR) systems have been used for the searching of relevant images in various research areas. In CBIR systems features such as shape, texture and color are used. The extraction of features is the main step on which the retrieval results depend. Color features in CBIR are used as in the color histogram, color moments, conventional color correlogram and color histogram. Color space selection is used to represent the information of color of the pixels of the query image. The shape is the basic characteristic of segmented regions of an image. Different methods are introduced for better retrieval using different shape representation techniques; earlier the global shape representations were used but with time moved towards local shape representations. The local shape is more related to the expressing of result instead of the method. Local shape features may be derived from the texture properties and the color derivatives. Texture features have been used for images of documents, segmentation-based recognition,and satellite images. Texture features are used in different CBIR systems along with color, shape, geometrical structure and sift features.
This document discusses clickjacking attacks, which hijack users' clicks to perform unintended actions. It provides an overview of clickjacking, describes different types of attacks, and analyzes vulnerabilities that make websites susceptible. Experiments are conducted on a sample social networking site, applying various clickjacking techniques. Potential defenses are tested, including X-Frame-Options headers and frame busting code. A proposed solution detects transparent iframes to warn users and check for hidden mouse pointers to mitigate cursorjacking. Analysis of top Jammu and Kashmir websites found most were vulnerable, while browser behavior studies showed varying support for defenses.
Performance Analysis of Audio and Video Synchronization using Spreaded Code D...Eswar Publications
The audio and video synchronization plays an important role in speech recognition and multimedia communication. The audio-video sync is a quite significant problem in live video conferencing. It is due to use of various hardware components which introduces variable delay and software environments. The objective of the synchronization is used to preserve the temporal alignment between the audio and video signals. This paper proposes the audio-video synchronization using spreading codes delay measurement technique. The performance of the proposed method made on home database and achieves 99% synchronization efficiency. The audio-visual
signature technique provides a significant reduction in audio-video sync problems and the performance analysis of audio and video synchronization in an effective way. This paper also implements an audio- video synchronizer and analyses its performance in an efficient manner by synchronization efficiency, audio-video time drift and audio-video delay parameters. The simulation result is carried out using mat lab simulation tools and simulink. It is automatically estimating and correcting the timing relationship between the audio and video signals and maintaining the Quality of Service.
Due to the availability of complicated devices in industry, models for consumers at lower cost of resources are developed. Home Automation systems have been developed by several researchers. The limitations of home automation includes complexity in architecture, higher costs of the equipment, interface inflexibility. In this paper as we have proposed, the working protocol of PIC 16F72 technology is which is secure, cost efficient, flexible that leads to the development of efficient home automation systems. The system is operational to control various home appliances like fans, Bulbs, Tube light. The following paper describes about components used and working of all components connected. The home automation system makes use of Android app entitled “Home App” which gives
flexibility and easy to use GUI.
Semantically Enchanced Personalised Adaptive E-Learning for General and Dysle...Eswar Publications
E-learning plays an important role in providing required and well formed knowledge to a learner. The medium of e- learning has achieved advancement in various fields such as adaptive e-learning systems. The need for enhancing e-learning semantically can enhance the retrieval and adaptability of the learning curriculum. This paper provides a semantically enhanced module based e-learning for computer science programme on a learnercentric perspective. The learners are categorized based on their proficiency for providing personalized learning environment for users. Learning disorders on the platform of e-learning still require lots of research. Therefore, this paper also provides a personalized assessment theoretical model for alphabet learning with learning objects for
children’s who face dyslexia.
Agriculture plays an important role in the economy of our country. Over 58 percent of the rural households depend on the agriculture sector as their means of livelihood. Agriculture is one of the major contributors to Gross Domestic Product(GDP). Seeds are the soul of agriculture. This application helps in reducing the time for the researchers as well as farmers to know the seedling parameters. The application helps the farmers to know about the percentage of seedlings that will grow and it is very essential in estimating the yield of that particular crop. Manual calculation may lead to some error, to minimize that error, the developed app is used. The scientist and farmers require the app to know about the physiological seed quality parameters and to take decisions regarding their farming activities. In this article a desktop app for seed germination percentage and vigour index calculation are developed in PHP scripting language.
What happens when adaptive video streaming players compete in time-varying ba...Eswar Publications
Competition among adaptive video streaming players severely diminishes user-QoE. When players compete at a bottleneck link many do not obtain adequate resources. This imbalance eventually causes ill effects such as screen flickering and video stalling. There have been many attempts in recent years to overcome some of these problems. However, added to the competition at the bottleneck link there is also the possibility of varying network bandwidth which can make the situation even worse. This work focuses on such a situation. It evaluates current heuristic adaptive video players at a bottleneck link with time-varying bandwidth conditions. Experimental setup includes the TAPAS player and emulated network conditions. The results show PANDA outperforms FESTIVE, ELASTIC and the Conventional players.
WLI-FCM and Artificial Neural Network Based Cloud Intrusion Detection SystemEswar Publications
Security and Performance aspects of cloud computing are the major issues which have to be tended to in Cloud Computing. Intrusion is one such basic and imperative security problem for Cloud Computing. Consequently, it is essential to create an Intrusion Detection System (IDS) to detect both inside and outside assaults with high detection precision in cloud environment. In this paper, cloud intrusion detection system at hypervisor layer is developed and assesses to detect the depraved activities in cloud computing environment. The cloud intrusion detection system uses a hybrid algorithm which is a fusion of WLI- FCM clustering algorithm and Back propagation artificial Neural Network to improve the detection accuracy of the cloud intrusion detection system. The proposed system is implemented and compared with K-means and classic FCM. The DARPA’s KDD cup dataset 1999 is used for simulation. From the detailed performance analysis, it is clear that the proposed system is able to detect the anomalies with high detection accuracy and low false alarm rate.
Spreading Trade Union Activities through Cyberspace: A Case StudyEswar Publications
This report present the outcome of an investigative research conducted to examine the modu-operandi of academic staff union of polytechnics (ASUP) YabaTech. The investigation covered the logistics and cost implication for spreading union activities among members. It was discovered that cost of management and dissemination of information to members was at high side, also logistics problem constitutes to loss of information in transit hence cut away some members from union activities. To curtail the problem identified, we proposed the
design of secure and dynamic website for spreading union activities among members and public. The proposed system was implemented using HTML5 technology, interface frameworks like Bootstrap and j query which enables the responsive feature of the application interface. The backend was designed using PHPMYSQL. It was discovered from the evaluation of the new system that cost of managing information has reduced considerably, and logistic problems identified in the old system has become a forgotten issue.
Identifying an Appropriate Model for Information Systems Integration in the O...Eswar Publications
Nowadays organizations are using information systems for optimizing processes in order to increase coordination and interoperability across the organizations. Since Oil and Gas Industry is one of the large industries in whole of the world, there is a need to compatibility of its Information Systems (IS) which consists three categories of systems: Field IS, Plant IS and Enterprise IS to create interoperability and approach the
optimizing processes as its result. In this paper we introduce the different models of information systems integration, identify the types of information systems that are using in the upstream and downstream sectors of petroleum industry, and finally based on expert’s opinions will identify a suitable model for information systems integration in this industry.
Link-and Node-Disjoint Evaluation of the Ad Hoc on Demand Multi-path Distance...Eswar Publications
This work illustrates the AOMDV routing protocol. Its ancestor, the AODV routing protocol is also described. This tutorial demonstrates how forward and reverse paths are created by the AOMDV routing protocol. Loop free paths formulation is described, together with node and link disjoint paths. Finally, the performance of the AOMDV routing protocol is investigated along link and node disjoint paths. The WSN with the AOMDV routing protocol using link disjoint paths is better than the WSN with the AOMDV routing protocol using node disjoint paths for energy consumption.
Bridging Centrality: Identifying Bridging Nodes in Transportation NetworkEswar Publications
To identify the importance of node of a network, several centralities are used. Majority of these centrality measures are dominated by components' degree due to their nature of looking at networks’ topology. We propose a centrality to identification model, bridging centrality, based on information flow and topological aspects. We apply bridging centrality on real world networks including the transportation network and show that the nodes distinguished by bridging centrality are well located on the connecting positions between highly connected regions. Bridging centrality can discriminate bridging nodes, the nodes with more information flowed through them and locations between highly connected regions, while other centrality measures cannot.
Now a days we are living in an era of Information Technology where each and every person has to become IT incumbent either intentionally or unintentionally. Technology plays a vital role in our day to day life since last few decades and somehow we all are depending on it in order to obtain maximum benefit and comfort. This new era equipped with latest advents of technology, enlightening world in the form of Internet of Things (IoT). Internet of things is such a specified and dignified domain which leads us to the real world scenarios where each object can perform some task while communicating with some other objects. The world with full of devices, sensors and other objects which will communicate and make human life far better and easier than ever. This paper provides an overview of current research work on IoT in terms of architecture, a technology used and applications. It also highlights all the issues related to technologies used for IoT, after the literature review of research work. The main purpose of this survey is to provide all the latest technologies, their corresponding
trends and details in the field of IoT in systematic manner. It will be helpful for further research.
Automatic Monitoring of Soil Moisture and Controlling of Irrigation SystemEswar Publications
In past couple of decades, there is immediate growth in field of agricultural technology. Utilization of proper method of irrigation by drip is very reasonable and proficient. A various drip irrigation methods have been proposed, but they have been found to be very luxurious and dense to use. The farmer has to maintain watch on irrigation schedule in the conventional drip irrigation system, which is different for different types of crops. In remotely monitored embedded system for irrigation purposes have become a new essential for farmer to accumulate his energy, time and money and will take place only when there will be requirement of water. In this approach, the soil test for chemical constituents, water content, and salinity and fertilizer requirement data collected by wireless and processed for better drip irrigation plan. This paper reviews different monitoring systems and proposes an automatic monitoring system model using Wireless Sensor Network (WSN) which helps the farmer to improve the yield.
Multi- Level Data Security Model for Big Data on Public Cloud: A New ModelEswar Publications
With the advent of cloud computing the big data has emerged as a very crucial technology. The certain type of cloud provides the consumers with the free services like storage, computational power etc. This paper is intended to make use of infrastructure as a service where the storage service from the public cloud providers is going to leveraged by an individual or organization. The paper will emphasize the model which can be used by anyone without any cost. They can store the confidential data without any type of security issue, as the data will be altered
in such a way that it cannot be understood by the intruder if any. Not only that but the user can retrieve back the original data within no time. The proposed security model is going to effectively and efficiently provide a robust security while data is on cloud infrastructure as well as when data is getting migrated towards cloud infrastructure or vice versa.
Impact of Technology on E-Banking; Cameroon PerspectivesEswar Publications
The financial services industry is experiencing rapid changes in services delivery and channels usage, and financial companies and users of financial services are looking at new technologies as they emerge and deciding whether or not to embrace them and the new opportunities to save and manage enormous time, cost and stress.
There is no doubt about the favourable and manifold impact of technology on e-banking as pictured in this review paper, almost all banks are with the least and most access e-banking Technological equipments like ATMs and Cards. On the other Hand cheap and readily available technology has opened a favourable competition in ebanking services business with a lot of wide range competitors competing with Commercial Banks in Cameroon in providing digital financial services.
Classification Algorithms with Attribute Selection: an evaluation study using...Eswar Publications
Attribute or feature selection plays an important role in the process of data mining. In general the data set contains more number of attributes. But in the process of effective classification not all attributes are relevant.
Attribute selection is a technique used to extract the ranking of attributes. Therefore, this paper presents a comparative evaluation study of classification algorithms before and after attribute selection using Waikato Environment for Knowledge Analysis (WEKA). The evaluation study concludes that the performance metrics of the classification algorithm, improves after performing attribute selection. This will reduce the work of processing irrelevant attributes.
Mining Frequent Patterns and Associations from the Smart meters using Bayesia...Eswar Publications
In today’s world migration of people from rural areas to urban areas is quite common. Health care services are one of the most challenging aspect that is must require to the people with abnormal health. Advancements in the technologies lead to build the smart homes, which contains various sensor or smart meter devices to automate the process of other electronic device. Additionally these smart meters can be able to capture the daily activities of the patients and also monitor the health conditions of the patients by mining the frequent patterns and
association rules generated from the smart meters. In this work we proposed a model that is able to monitor the activities of the patients in home and can send the daily activities to the corresponding doctor. We can extract the frequent patterns and association rules from the log data and can predict the health conditions of the patients and can give the suggestions according to the prediction. Our work is divided in to three stages. Firstly, we used to record the daily activities of the patient using a specific time period at three regular intervals. Secondly we applied the frequent pattern growth for extracting the association rules from the log file. Finally, we applied k means clustering for the input and applied Bayesian network model to predict the health behavior of the patient and precautions will be given accordingly.
Network as a Service Model in Cloud Authentication by HMAC AlgorithmEswar Publications
Resource pooling on internet-based accessing on use as pay environmental technology and ruled in IT field is the
cloud. Present, in every organization has trusted the web, however, the information must flow but not hold the
data. Therefore, all customers have to use the cloud. While the cloud progressing info by securing-protocols. Third
party observing and certain circumstances directly stale in flow and kept of packets in the virtual private cloud.
Global security statistics in the year 2017, hacking sensitive information in cloud approximately maybe 75.35%,
and the world security analyzer said this calculation maybe reached to 100%. For this cause, this proposed
research work concentrates on Authentication-Message-Digest-Key with authentication in routing the Network as
a Service of packets in OSPF (Open Shortest Path First) implementing Cloud with GNS3 has tested them to
securing from attackers.
Microstrip patch antennas are recently used in wireless detection applications due to their low power consumption, low cost, versatility, field excitation, ease of fabrication etc. The microstrip patch antennas are also called as printed antennas which is suffer with an array elements of antenna and narrow bandwidth. To overcome the above drawbacks, Flame Retardant Material is used as the substrate. Rectangular shape of microstrip patch antenna with FR4 material as the substrate which is more suitable for the explosive detection applications. The proposed printed antenna was designed with the dimension of 60 x 60 mm2. FR-4 material has a dielectric constant value of 4.3 with thickness 1.56 mm, length and width 60 mm and 60 mm respectively. One side of the substrate contains the ground plane of dimensions 60 x60 mm2 made of copper and the other side of the substrate contains the patch which have dimensions 34 x 29 mm2 and thickness 0.03mm which is also made of copper. RMPA without slot, Vertical slot RMPA, Double horizontal slot RMPA and Centre slot RMPA structures were
designed and the performance of the antennas were analysed with various parameters such as gain, directivity, Efield, VSWR and return loss. From the performance analysis, double horizontal slot RMPA antenna provides a better result and it provides maximum gain (8.61dB) and minimum return loss (-33.918dB). Based on the E-field excitation value the SEMTEX explosive material is detected and it was simulated using CST software.
Unlocking Productivity: Leveraging the Potential of Copilot in Microsoft 365, a presentation by Christoforos Vlachos, Senior Solutions Manager – Modern Workplace, Uni Systems
In his public lecture, Christian Timmerer provides insights into the fascinating history of video streaming, starting from its humble beginnings before YouTube to the groundbreaking technologies that now dominate platforms like Netflix and ORF ON. Timmerer also presents provocative contributions of his own that have significantly influenced the industry. He concludes by looking at future challenges and invites the audience to join in a discussion.
Fueling AI with Great Data with Airbyte WebinarZilliz
This talk will focus on how to collect data from a variety of sources, leveraging this data for RAG and other GenAI use cases, and finally charting your course to productionalization.
Climate Impact of Software Testing at Nordic Testing DaysKari Kakkonen
My slides at Nordic Testing Days 6.6.2024
Climate impact / sustainability of software testing discussed on the talk. ICT and testing must carry their part of global responsibility to help with the climat warming. We can minimize the carbon footprint but we can also have a carbon handprint, a positive impact on the climate. Quality characteristics can be added with sustainability, and then measured continuously. Test environments can be used less, and in smaller scale and on demand. Test techniques can be used in optimizing or minimizing number of tests. Test automation can be used to speed up testing.
TrustArc Webinar - 2024 Global Privacy SurveyTrustArc
How does your privacy program stack up against your peers? What challenges are privacy teams tackling and prioritizing in 2024?
In the fifth annual Global Privacy Benchmarks Survey, we asked over 1,800 global privacy professionals and business executives to share their perspectives on the current state of privacy inside and outside of their organizations. This year’s report focused on emerging areas of importance for privacy and compliance professionals, including considerations and implications of Artificial Intelligence (AI) technologies, building brand trust, and different approaches for achieving higher privacy competence scores.
See how organizational priorities and strategic approaches to data security and privacy are evolving around the globe.
This webinar will review:
- The top 10 privacy insights from the fifth annual Global Privacy Benchmarks Survey
- The top challenges for privacy leaders, practitioners, and organizations in 2024
- Key themes to consider in developing and maintaining your privacy program
Infrastructure Challenges in Scaling RAG with Custom AI modelsZilliz
Building Retrieval-Augmented Generation (RAG) systems with open-source and custom AI models is a complex task. This talk explores the challenges in productionizing RAG systems, including retrieval performance, response synthesis, and evaluation. We’ll discuss how to leverage open-source models like text embeddings, language models, and custom fine-tuned models to enhance RAG performance. Additionally, we’ll cover how BentoML can help orchestrate and scale these AI components efficiently, ensuring seamless deployment and management of RAG systems in the cloud.
Essentials of Automations: The Art of Triggers and Actions in FMESafe Software
In this second installment of our Essentials of Automations webinar series, we’ll explore the landscape of triggers and actions, guiding you through the nuances of authoring and adapting workspaces for seamless automations. Gain an understanding of the full spectrum of triggers and actions available in FME, empowering you to enhance your workspaces for efficient automation.
We’ll kick things off by showcasing the most commonly used event-based triggers, introducing you to various automation workflows like manual triggers, schedules, directory watchers, and more. Plus, see how these elements play out in real scenarios.
Whether you’re tweaking your current setup or building from the ground up, this session will arm you with the tools and insights needed to transform your FME usage into a powerhouse of productivity. Join us to discover effective strategies that simplify complex processes, enhancing your productivity and transforming your data management practices with FME. Let’s turn complexity into clarity and make your workspaces work wonders!
How to Get CNIC Information System with Paksim Ga.pptxdanishmna97
Pakdata Cf is a groundbreaking system designed to streamline and facilitate access to CNIC information. This innovative platform leverages advanced technology to provide users with efficient and secure access to their CNIC details.
Things to Consider When Choosing a Website Developer for your Website | FODUUFODUU
Choosing the right website developer is crucial for your business. This article covers essential factors to consider, including experience, portfolio, technical skills, communication, pricing, reputation & reviews, cost and budget considerations and post-launch support. Make an informed decision to ensure your website meets your business goals.
Taking AI to the Next Level in Manufacturing.pdfssuserfac0301
Read Taking AI to the Next Level in Manufacturing to gain insights on AI adoption in the manufacturing industry, such as:
1. How quickly AI is being implemented in manufacturing.
2. Which barriers stand in the way of AI adoption.
3. How data quality and governance form the backbone of AI.
4. Organizational processes and structures that may inhibit effective AI adoption.
6. Ideas and approaches to help build your organization's AI strategy.
HCL Notes und Domino Lizenzkostenreduzierung in der Welt von DLAUpanagenda
Webinar Recording: https://www.panagenda.com/webinars/hcl-notes-und-domino-lizenzkostenreduzierung-in-der-welt-von-dlau/
DLAU und die Lizenzen nach dem CCB- und CCX-Modell sind für viele in der HCL-Community seit letztem Jahr ein heißes Thema. Als Notes- oder Domino-Kunde haben Sie vielleicht mit unerwartet hohen Benutzerzahlen und Lizenzgebühren zu kämpfen. Sie fragen sich vielleicht, wie diese neue Art der Lizenzierung funktioniert und welchen Nutzen sie Ihnen bringt. Vor allem wollen Sie sicherlich Ihr Budget einhalten und Kosten sparen, wo immer möglich. Das verstehen wir und wir möchten Ihnen dabei helfen!
Wir erklären Ihnen, wie Sie häufige Konfigurationsprobleme lösen können, die dazu führen können, dass mehr Benutzer gezählt werden als nötig, und wie Sie überflüssige oder ungenutzte Konten identifizieren und entfernen können, um Geld zu sparen. Es gibt auch einige Ansätze, die zu unnötigen Ausgaben führen können, z. B. wenn ein Personendokument anstelle eines Mail-Ins für geteilte Mailboxen verwendet wird. Wir zeigen Ihnen solche Fälle und deren Lösungen. Und natürlich erklären wir Ihnen das neue Lizenzmodell.
Nehmen Sie an diesem Webinar teil, bei dem HCL-Ambassador Marc Thomas und Gastredner Franz Walder Ihnen diese neue Welt näherbringen. Es vermittelt Ihnen die Tools und das Know-how, um den Überblick zu bewahren. Sie werden in der Lage sein, Ihre Kosten durch eine optimierte Domino-Konfiguration zu reduzieren und auch in Zukunft gering zu halten.
Diese Themen werden behandelt
- Reduzierung der Lizenzkosten durch Auffinden und Beheben von Fehlkonfigurationen und überflüssigen Konten
- Wie funktionieren CCB- und CCX-Lizenzen wirklich?
- Verstehen des DLAU-Tools und wie man es am besten nutzt
- Tipps für häufige Problembereiche, wie z. B. Team-Postfächer, Funktions-/Testbenutzer usw.
- Praxisbeispiele und Best Practices zum sofortigen Umsetzen
In the rapidly evolving landscape of technologies, XML continues to play a vital role in structuring, storing, and transporting data across diverse systems. The recent advancements in artificial intelligence (AI) present new methodologies for enhancing XML development workflows, introducing efficiency, automation, and intelligent capabilities. This presentation will outline the scope and perspective of utilizing AI in XML development. The potential benefits and the possible pitfalls will be highlighted, providing a balanced view of the subject.
We will explore the capabilities of AI in understanding XML markup languages and autonomously creating structured XML content. Additionally, we will examine the capacity of AI to enrich plain text with appropriate XML markup. Practical examples and methodological guidelines will be provided to elucidate how AI can be effectively prompted to interpret and generate accurate XML markup.
Further emphasis will be placed on the role of AI in developing XSLT, or schemas such as XSD and Schematron. We will address the techniques and strategies adopted to create prompts for generating code, explaining code, or refactoring the code, and the results achieved.
The discussion will extend to how AI can be used to transform XML content. In particular, the focus will be on the use of AI XPath extension functions in XSLT, Schematron, Schematron Quick Fixes, or for XML content refactoring.
The presentation aims to deliver a comprehensive overview of AI usage in XML development, providing attendees with the necessary knowledge to make informed decisions. Whether you’re at the early stages of adopting AI or considering integrating it in advanced XML development, this presentation will cover all levels of expertise.
By highlighting the potential advantages and challenges of integrating AI with XML development tools and languages, the presentation seeks to inspire thoughtful conversation around the future of XML development. We’ll not only delve into the technical aspects of AI-powered XML development but also discuss practical implications and possible future directions.
Monitoring and Managing Anomaly Detection on OpenShift.pdfTosin Akinosho
Monitoring and Managing Anomaly Detection on OpenShift
Overview
Dive into the world of anomaly detection on edge devices with our comprehensive hands-on tutorial. This SlideShare presentation will guide you through the entire process, from data collection and model training to edge deployment and real-time monitoring. Perfect for those looking to implement robust anomaly detection systems on resource-constrained IoT/edge devices.
Key Topics Covered
1. Introduction to Anomaly Detection
- Understand the fundamentals of anomaly detection and its importance in identifying unusual behavior or failures in systems.
2. Understanding Edge (IoT)
- Learn about edge computing and IoT, and how they enable real-time data processing and decision-making at the source.
3. What is ArgoCD?
- Discover ArgoCD, a declarative, GitOps continuous delivery tool for Kubernetes, and its role in deploying applications on edge devices.
4. Deployment Using ArgoCD for Edge Devices
- Step-by-step guide on deploying anomaly detection models on edge devices using ArgoCD.
5. Introduction to Apache Kafka and S3
- Explore Apache Kafka for real-time data streaming and Amazon S3 for scalable storage solutions.
6. Viewing Kafka Messages in the Data Lake
- Learn how to view and analyze Kafka messages stored in a data lake for better insights.
7. What is Prometheus?
- Get to know Prometheus, an open-source monitoring and alerting toolkit, and its application in monitoring edge devices.
8. Monitoring Application Metrics with Prometheus
- Detailed instructions on setting up Prometheus to monitor the performance and health of your anomaly detection system.
9. What is Camel K?
- Introduction to Camel K, a lightweight integration framework built on Apache Camel, designed for Kubernetes.
10. Configuring Camel K Integrations for Data Pipelines
- Learn how to configure Camel K for seamless data pipeline integrations in your anomaly detection workflow.
11. What is a Jupyter Notebook?
- Overview of Jupyter Notebooks, an open-source web application for creating and sharing documents with live code, equations, visualizations, and narrative text.
12. Jupyter Notebooks with Code Examples
- Hands-on examples and code snippets in Jupyter Notebooks to help you implement and test anomaly detection models.
AI-Powered Food Delivery Transforming App Development in Saudi Arabia.pdfTechgropse Pvt.Ltd.
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Review of Some Checkpointing Schemes for Distributed and Mobile Computing Environments
1. Int. J. Advanced Networking and Applications
Volume: 06 Issue: 06 Pages: 2542-2548 (2015) ISSN: 0975-0290
2542
Review of Some Checkpointing Schemes for
Distributed and Mobile Computing
Environments
Mr Raman Kumar
Mewar University, Chittorgargh (Raj)
Email: rmn.kmr1@gmail.com
Dr Parveen Kumar
Amity University Gurgaon (Haryana)
Email: pk223475@gmail.com
---------------------------------------------------------------------ABSTRACT-------------------------------------------------------
Fault Tolerance Techniques facilitate systems to carry out tasks in the incidence of faults. A checkpoint is a local
state of a process saved on stable storage. In a distributed system, since the processes in the system do not share
memory; a global state of the system is defined as a combination of local states, one from each process. In case of a
fault in distributed systems, checkpointing enables the execution of a program to be resumed from a previous
consistent global state rather than resuming the execution from the commencement. In this way, the sum of
constructive processing vanished because of the fault is appreciably reduced. In this paper, we talk about various
issues related to the checkpointing for distributed systems and mobile computing environments. We also confer
various types of checkpointing: coordinated checkpointing, asynchronous checkpointing, communication induced
checkpointing and message logging based checkpointing. We also present a survey of some checkpointing
algorithms for distributed systems.
Keywords: Check pointing algorithms; parallel & distributed computing; rollback recovery; fault-tolerant
systems.
------------------------------------------------------------------------------------------------------------------------------------------
Date of Submission: December 24, 2014 Date of Acceptance: February 15, 2015
------------------------------------------------------------------------------------------------------------------------------------------
1. INTRODUCTION
1.1 Distribution Systems and Mobile Systems
A distributed system is a compilation of self-
governing entities that work together to solve a problem
that cannot be individually solved. A distributed system
can be characterized as a collection of mostly
autonomous processors communicating over a
communication network [24].
In a distributed system, there exists no system
wide common clock (global clock). In other words, the
notion of global time does not exist. Suppose a global
(common) clock is available for all the processes in the
system. In this case, two different processes can observe
a global clock value at different instants due to
unpredictable message transmission delays [24].
Due to the absence of global time and shared
memory, it is difficult to reason about the temporal
order of events in a distributed system. Hence,
algorithms for a distributed system are more
complicated to design and debug compared to
algorithms for centralized systems. In addition, the
nonexistence of a global clock makes it harder to
accumulate up to- date information on the state of the
whole system [24].
In mobile distributed computing system,
some processes are operating on mobile hosts (MHs).
An MH is a computer that may retain its connectivity
with the rest of the distributed system through a
wireless network while on move or it may disconnect. It
requires integration of portable computers within
existing data network. An MH can connect to the
network from different locations at different times. The
infrastructure machines that communicate directly with
the MHs are called Mobile Support Stations (MSSs).
A cell is a logical or geographical coverage area under
an MSS. All MHs that have identified themselves with
a particular MSS are considered to be local to the MSS.
An MH can straightforwardly converse with an MSS
(and vice-versa) only if the MH is physically positioned
within the cell serviced by the MSS. At any given
moment of time, an MH may logically belong to only
one cell; its current cell defines the MH’s location [25].
To throw a message from an MH h1 to
another MH h2, h1 first sends the communication to its
local MSS over the wireless network. This MSS then
forwards the communication to the local MSS of h2
which forwards it to h2 over its local wireless network
[25].
Many Algorithms for MHs may make use of
a handoff modus operandi: when an MH switches cell,
MSS of the two cells carry out the handoff procedure.
An MSS may preserve algorithm specific data
structures on the behalf of a local MH. When an MH
moves into a new cell, data structures from the previous
MSS are transferred to the new MSS. For this to be
realized, it is compulsory that the MH either inform the
previous MSS of the ID of this new MSS or vice-versa.
It should be like that an MH supply the ID of its
previous MSS after inflowing the new cell with the join
() message [25].
2. Int. J. Advanced Networking and Applications
Volume: 06 Issue: 06 Pages: 2542-2548 (2015) ISSN: 0975-0290
2543
Disconnection is handled in a parallel way to an MH
switching cells. Disconnection is unlike from failure.
Disconnections are optional or volunteer by nature, so
an MH informs the system prior to its happening and
executes an application-specific disconnection
procedure if necessary. Disconnection can be deliberate
or uncontrolled. The term “disconnection” implies a
voluntary disconnection. An unexpected or
unintentional disconnection is considered to be a failure
[25].
1.2 Software Based Fault Tolerance
Fault tolerance can be achieved through some kind of
redundancy. Redundancy can be temporal or spatial. In
spatial redundancy or hardware-based fault tolerance,
many copies of the application execute on diverse
processors concurrently and stringent timing constraints
can be met. But the outlay of providing fault tolerance
using spatial redundancy is fairly high and may require
additional hardware. In temporal redundancy or
software-based fault tolerance, an application is
restarted from a former checkpoint or recovery point
after a fault. This may result in the thrashing of some
processing and applications may not be able to meet
stringent timing targets. Checkpoint-Restart or
Backward error recovery is quite inexpensive and does
not require extra hardware in general. Besides providing
fault tolerance, checkpointing can be used for process
migration, debugging distributed applications; job
swapping, postmortem analysis and stable property
detection [24].There are two software based fault
tolerance approaches for error recovery:
• Forward Error Recovery
• Backward Error Recovery
In forward error recovery techniques, the character of
errors and damage caused by faults must be wholly and
precisely assessed and so it becomes possible to
eliminate those errors in the process state and enable the
process to move onward [27]. In distributed system,
precise estimation of all the faults may not be possible.
In backward error recovery techniques, the nature of
faults need not be predicted and in case of error, the
process state is restored to preceding error-free state. It
is independent of the nature of faults. Thus, backward
error recovery is more common recovery mechanism
[24].
1.3 Definitions and Notations
Checkpoint: Checkpoint is defined as a selected place
in a program at which normal process is broken up
specifically to conserve the status information necessary
to allow recommencement of processing at a later time.
A checkpoint is a local state of a process saved on
stable storage. By periodically invoking the
checkpointing process, one can save the status of a
program at regular intervals [24].
Rollback Recovery: If there is a failure one may
restart computation from the last checkpoints, thereby,
avoiding repeating computation from the
commencement. The process of resuming computation
by rolling back to a saved state is called rollback
recovery [24, 27].
Global State: In a distributed system, since the
processes in the system do not share memory, a global
state of the system is defined as a set of local states, one
from each process. The state of channels corresponding
to a global state is the set of communication sent but not
yet received [24, 27].
Orphan Message: A message whose receive event is
recorded, but its send event is lost in the recorded
global state.
Consistent Global State: A global state is said to be
“consistent” if it contains no orphan message. To
recover from a failure, the system restarts its execution
from a previous consistent global state saved on the
stable storage during fault-free execution. In distributed
systems, checkpointing can be independent, coordinated
or quasi-synchronous. Message Logging is also used for
fault tolerance in distributed systems [24, 27].
Asynchronous Checkpointing: Under the
asynchronous approach, checkpoints at each process are
taken independently without any synchronization
among the processes. Because of absence of
synchronization, there is no guarantee that a set of local
checkpoints taken will be a consistent set of
checkpoints. It may require cascaded rollbacks that may
lead to the initial state due to domino-effect [27].
Coordinated Checkpointing: In coordinated or
synchronous Checkpointing, processes take checkpoints
in such a manner that the resulting global state is
consistent. Mostly it follows two-phase commit
structure [27]. In the first phase, processes take tentative
checkpoints and in the second phase, these are made
permanent. The main advantage is that only one
permanent checkpoint and at most one tentative
checkpoint is required to be stored. In the case of a
fault, processes rollback to the last check pointed state.
Communication-induced Checkpointing: It avoids
the domino-effect without requiring all checkpoints to
be coordinated [24]. In these protocols, processes take
two kinds of checkpoints, local and forced. Local
checkpoints can be taken independently, while forced
checkpoints are taken to guarantee the eventual
progress of the recovery line and to minimize useless
checkpoints. As opposed to coordinated checkpointing,
these protocols do no exchange any special
coordination messages to determine when forced
checkpoints should be taken. But, they piggyback
protocol specific information [generally checkpoint
sequence numbers] on each application message; the
receiver then uses this information to decide if it should
take a forced checkpoint.
Deterministic Systems: If two processes start in the
same state, and both receive the identical sequence of
inputs, they will produce the identical sequence outputs
and will finish in the same state. The state of a process
is thus completely determined by its starting state and
by sequence of messages it has received [23, [24], [25].
Checkpoint Interval (CI): The ith
CI of a process
denotes all the computation performed between its ith
and (i+1)th
checkpoint, including the ith
checkpoint but
not the (i+1)th
checkpoint.
3. Int. J. Advanced Networking and Applications
Volume: 06 Issue: 06 Pages: 2542-2548 (2015) ISSN: 0975-0290
2544
Direct Dependency among Processes: Pj is directly
dependent upon Pk only if there exists m such that Pj
receives m from Pk in the current CI and Pk has not
taken its permanent checkpoint after sending m.
Minimum Set: A process Pi is in the minimum set only
if checkpoint initiator process is transitively dependent
upon it.
Minimum-process Coordinated Checkpointing
Algorithms : In these algorithms, only a subset of
interacting processes (called minimum set) are required
to take checkpoints in an initiation.
Anti-Message: David R. Jefferson [29] introduced the
concept of anti-message. Anti-message is precisely like
an original message in format and content except in one
field, its sign. Two messages that are identical except
for opposite signs are called anti-messages of one
another. All messages sent explicitly by user programs
have a positive (+) sign; and their anti-messages have a
negative sign (-). Whenever a message and its anti-
message occur in the same queue, they immediately
eradicate one another. Thus the result of enqueueing a
message may be to shorten the queue by one message
rather than lengthen it by one.
2. LITERATURE SURVEY
2.1 Chandy and Lamport Algorithm [1]
They designed a global snapshot algorithm for
distributed systems. It is observed that every
checkpointing algorithm proposed for message passing
system uses Chandy and Lamport’s algorithm as the
foundation. The algorithms proposed in literature for
message passing systems may be derived by relaxing
various assumptions made by the demand modifying
the way each step is carried out.
The steps are below:
(1) Save the local context in a stable storage.
(2) For i = 1 to all outgoing channels do send
markers along channel i;
(3) Continue regular computation;
(4) For i=1 to all incoming channels do Save
incoming messages in channel i until a marker I is
received along that channel.
Each step of CL algorithm can be modified to
accommodate some improvements in basic global
snapshot algorithm.
In Step 1 node saves its context in stable storage .The
overhead associated with step one is context saving
overhead. The objective of saving context in stable
storage is to ensure its availability after a node failure
.The overhead of context saving is proportional to the
size of context and the time taken to access the stable
storage. Context saving overhead can be reduced by (a)
minimizing the context size and (b) overlapping context
saving with computation.
In Step 2 markers are sent along all outgoing channels
.The purpose of a marker is
(1) To inform the receiving node that a new checkpoint
has to be taken;
(2) To separate the messages of the previous and
current checkpoint interval.
2.2 Wang and Fuchs Lazy Algorithm [17]
The lazy new algorithm work as on receiving a marker
from process p , process q, “remembers” the marker
(marks the channel dirty) of marker from p. It sends
markers on all outgoing channels as usual. However q
does not need along all outgoing channels postpones the
recording of its local state . Local state recording can be
postponed to a later time .q is forced to take a local
snapshot only if q receives a message from a process p.
a marker from which it has already received. By
delaying the recording of a local snapshot the number
of in- transit message is decreased. Thus, a process can
reduce the amount of channel state that
it needs to record with the snapshot. The ability to
postpone recording local state also has the advantage of
giving process flexibility in scheduling this potentially
expensive task.
There is one technical problem with the deferment as
described, however. Consider the case of a process r
that does not converse with the rest of the system. This
process could just execute some local computation,
never sending or receiving messages to the other
processes. In such a case, all other processes in the
system could take their local snapshots, but the global
snapshot cannot be calculated until r records its local
state.
In order to force the global state collector to terminate,
a third event can be added: A marker has
been received on every incoming channel. The local
snapshot triggered by this event will record the state of
every incoming channel as empty.
2.3 Venkatesan’s Incremental method [19]:
Venkatesan proposed an incremental approach to
collecting global snapshots. Using this solution each
approach maintains the most recent snapshots taken. A
new local snapshot would then just involve combining
the local state change since the last snapshot with the
most recent snapshot. This algorithm assumes the
presence of only a single initiator process.
2.4 Koo-Toueg Alogritham [5]:
Koo and Toueg have shown that if the nodes capture
their local snapshots in an uncoordinated manner, it
may not be possible to assemble a consistent global
state from such snapshots. The rollback may lead to
domino effect. In Synchronous snapshot collection
algorithm a node initiates snapshot collection by taking
its local snapshot then it sends request message to
another nodes to take their snapshot. If the nodes
maintain information about casual dependencies a
minimal number of nodes have to take their local
snapshots in reaction to such requirements. Koo and
Toueg had presented such an algorithm which involves
suspending the underlying computation during snapshot
compilation .The nodes resume the underlying when the
snapshot collection terminates. Koo and Toueg have
planned methods to handle concurrent initiations of
snapshot collection. They handle concurrent snapshot
collection in following way. Once a node takes a local
snapshot, it is unwilling to take a snapshot in response
to another initiator. The node sends a negative response
to all subsequent requests until the snapshot request is
4. Int. J. Advanced Networking and Applications
Volume: 06 Issue: 06 Pages: 2542-2548 (2015) ISSN: 0975-0290
2545
made permanent or until the snapshot collection is
aborted. Their algorithm makes the following
assumption about distributed system: processes
communicate by exchanging messages through
communication channels. Communication channels are
FIFO. Communication failure does not partition the
network. The Checkpoint algorithm takes two kinds of
checkpoints on stable storage: Permanent and tentative.
A permanent checkpoint is a local checkpoint at a
process and is a part of a consistent global checkpoint
.A tentative checkpoint is a temporary checkpoint that
is made permanent checkpoint on successful
termination of checkpointing algorithm .In case of a
failure processes rollback only to their permanent
checkpoints for recovery .The algorithm assumes that
no process fails during the execution of algorithm .The
algorithm consists of two phases
First Phase
An initiating process Pi captures a tentative checkpoint
and requests all other processes to capture tentative
checkpoints. Each process informs Pi whether it
succeeded in taking a tentative checkpoint. A process
says “no” to a request if it fails to take tentative
checkpoint which would be due to numerous reasons
depending on underlying function. If Pi learns that all
the processes have effectively taken tentative
checkpoints Pi decides that all tentative checkpoints
should be made enduring; otherwise Pi decides that all
the tentative checkpoints should be superfluous.
Second Phase
Pi informs all the processes that their verdict had been
reach at the end of first phase. A process on receiving
the message from Pi will act consequently. Therefore,
either all or none of processes move ahead the
checkpoint by taking permanent checkpoints. The
algorithm requires that after a process has taken a
tentative checkpoint it cannot send communications
related to underlying computation until it informed of
Pi’s verdict.
2.5 Silva L, Silva J Alogrithm [16]:
They designed an all process synchronous
checkpointing protocol for distributed systems. The
non- intrusiveness during checkpointing is attained by
piggybacking ever-increasing checkpoint numbers
along with computational messages. When a process
receives a computational message with the high
checkpoint number, it captures its checkpoint before
processing the message. When it truly gets the
checkpoint request from the initiator, it ignores the
same. If each process of the distributed program is
permitted to initiate the checkpoint operation, the
network may be swamped with control messages and
process might misuse their time capturing unnecessary
checkpoints. In order to avoid this, Silva and Silva gave
the key to initiate checkpoint algorithm to one process.
The checkpoint event is triggered periodically by a local
timer mechanism. When this timer expires, the initiator
process checkpoint the state of process running in the
machine and force all the others to take checkpoint by
sending a broadcast message. The interval between
adjacent checkpoints is called checkpoint interval.
2.6 J.L.Kim and T.Park Algorithm [11] :
Kim-Park Algorithm proposed a protocol for
checkpointing recovery which exploits the dependency
relationship between processes to achieve time-
efficiency in checkpointing and rollback coordination.
Unlike other synchronized protocols. In which the
checkpointing coordinator collects the status
information of the processes that it depends on and
delivers its decision, the process in their protocol takes
a checkpoint when it knows that all processes on which
it computationally depends took their checkpoints. In
this way, the coordinator of the checkpointing does not
always have to deliver its decision after it collects the
status of the processes it depends on hence one phase of
the coordination is practically removed. The
checkpointing coordination time and the possibility of
total abort of the checkpointing are substantially
reduced. Reduction of the coordination roll back time is
also achieved by sending the restart messages from the
coordinator directly to the roll back process. and
concurrent activities of the checkpointing and roll back
are effectively handled exploiting the process
dependency relationship.
2.7 Ravi Prakash and Mukesh Singhal Algorithm [7]:
They had described a Synchronous Snapshot
compilation algorithm for Mobile Systems that neither
forces every node to take a local snapshot nor blocks
the essential computation during snapshot collection. If
a node initiates snapshot collection, local snapshot of
only those nodes that have directly or transitively
affected the initiator, take their checkpoints. This paper
presents that the global snapshot collection terminates
within a finite time of its request and collected global
snapshot is consistent. This paper presents a minimal
rollback/recovery algorithm in which the computation
at a node is rolled back only if depends on operations
that have been undone due to failure of node(s).Both the
algorithms have low communication and storage
overheads and meet the low energy consumption and
low bandwidth constraints of mobile computing
systems. The synchronous snapshot collection
algorithm that accounts for the mobility of the nodes
.The algorithm forces a minimal set of nodes to take
their snapshots and underlying computation is not
suspended during snapshot collection .An interesting
aspect of the algorithm is that it has lazy phase that
enables nodes to take local snapshots in quasi-
asynchronous fashion, after the coordinated snapshot
collection phase is over. This further reduces the
amount of computation that is rollback during recovery
from node failure. The lazy phase advances the
checkpoint slowly rather than in a burst. This avoids
disagreement for the low bandwidth channels. This
algorithm also considers the changing topology of
network due to mobility of nodes. Here the Recovery
algorithm is a compromise between two diverse
recovery strategies – fast recovery with high
5. Int. J. Advanced Networking and Applications
Volume: 06 Issue: 06 Pages: 2542-2548 (2015) ISSN: 0975-0290
2546
communication and storage overhead and slow recovery
with very little communication overhead.
2.8 Coa and Singhal Minimum-process Blocking
Scheme [6]
They presented a minimum process checkpointing
algorithm in which, the dependency information is
recorded by a Boolean vector. This algorithm is a two-
phase protocol and saves two kinds of checkpoint on
the stable storage. In the first phase, the initiator sends a
request to all processes to send their dependency vector.
On receiving the request, each process sends its
dependency vector. Having received all the dependency
vectors, the initiator constructs an N*N dependency
matrix with one row per process, represented by the
dependency vector of the process, Based on the
dependency matrix, the initiator can locally calculate all
the process on which the initiator transitively depends.
After the initiator finds all the process that need to take
their checkpoints, it adds them to the set Sforced and asks
them to take checkpoints. Any process receiving a
checkpoint request takes the checkpoint and sends a
reply. The process has to be blocked after receiving the
dependency vectors request and resumes its
computation after receiving a checkpoint request.
2.9 Cao-Singhal Non-intrusive Checkpointing
Algorithm [2]:
They proved that no min-process non-blocking
algorithm exists. There are two directions in designing
efficient coordinated checkpointing algorithms. First is
to relax the non-blocking condition while keeping the
min-process property. The other is to relax the min-
process condition while keeping the non-blocking
property. The new constraints in mobile computing
system, such as low bandwidth of wireless channel,
high search cost, and limited battery life, suggest that
the proposed checkpointing algorithm should be a min-
process algorithm. Therefore, they developed an
algorithm that relaxes the min-process condition. In
this scheme, they introduced the concept of mutable
checkpoint, which is neither a tentative checkpoint nor
a permanent checkpoint, to design efficient
checkpointing algorithms for mobile computing
systems. Mutable checkpoints can be saved anywhere,
e.g., the main memory or local disk of MHs.
Such algorithms rely on the two-phase commit protocol
and save two kinds of checkpoints on the stable storage:
tentative and permanent.
In the first phase, the initiator takes a tentative
checkpoint and forces all relevant processes to take
tentative checkpoints. Each process informs the initiator
whether it succeeded in taking a tentative checkpoint.
When the initiator learns that all relevant processes
have successfully taken tentative checkpoints, it asks
them to make their tentative checkpoints permanent;
otherwise, it asks them to discard them. A process, on
receiving the message from the initiator, acts
accordingly. A non-blocking checkpointing algorithm
does not require any process to suspend its underlying
computation. When processes do not suspend their
computations, it is possible for a process to receive a
computation message from another process which is
already running in a new checkpoint interval. If this
situation is not properly handled, it may result in an
inconsistency.
In their algorithm, initiator, say Pin, sends the
checkpoint request to any process, say Pj, only if Pin
receives m from Pj in the current CI. Pj takes its
tentative checkpoint if Pj has sent m to Pin in the current
CI; otherwise, Pj concludes that the checkpoint request
is a useless one. Similarly, when Pj takes its tentative
checkpoint, it propagates the checkpoint request to
other processes. This process is continued till the
checkpoint request reaches all the processes on which
the initiator transitively depends and a checkpointing
tree is formed. During checkpointing, if Pi receives m
from Pj such that Pj has taken some checkpoint in the
current initiation before sending m, Pi may be forced to
take a checkpoint, called mutable checkpoint. If Pi is not
in the minimum set, its mutable checkpoint is useless
and is discarded on commit. The huge data structure
MR[] is also attached with the checkpoint requests to
reduce the number of useless checkpoint requests. The
response from each process is sent directly to initiator.
2.10 P. Kumar and L. Kumar algorithm [3] :
In Cao and Singhal algorithm number of useless
checkpoint may exceeding high in some situation [2].
P. Kumar and L. Kumar proposed a new for
Synchronous check pointing protocol for mobile
distributed system [3]. They are able to maintain exact
dependencies among processes and make an
approximate set of interacting processes at the
beginning. In this way the time to collect coordinated
checkpoint is reduced. The number of useless check
pointing and blocking processes is also reduced. A
process checkpoint if the probability that it will get a
checkpoint request in current initiation is high. A few
processes may be blocked but they can continue their
normal computation and may send message..
Suppose, during the execution of the check pointing
algorithm, Pi takes its checkpoint and sends m to Pj. Pj
receives m such that it has not taken its checkpoint for
the current initiation and it does not know whether it
will get the checkpoint request. If Pj takes its
checkpoint after processing m, m will become orphan.
In order to avoid such orphan messages, they propose
the following technique. If Pj has sent at least one
message to a process, say Pk and Pk is in the tentative
minimum set, there is a good probability that Pj will get
the checkpoint request. Therefore, Pj takes its induced
checkpoint before processing m. An induced checkpoint
is similar to the mutable checkpoint [14]. In this case,
most probably, Pj will get the checkpoint request and its
induced checkpoint will be converted into permanent
one. There is a less probability that Pj will not get the
checkpoint request and its induced checkpoint will be
discarded. Alternatively, if there is not a good
probability that Pj will get the checkpoint request, Pj
buffers m till it takes its checkpoint or receives the
commit message. They have tried to minimize the
number of useless checkpoints and blocking of the
6. Int. J. Advanced Networking and Applications
Volume: 06 Issue: 06 Pages: 2542-2548 (2015) ISSN: 0975-0290
2547
process by using the probabilistic approach and
buffering selective messages at the receiver end. Exact
dependencies among processes are maintained. It
abolishes the useless checkpoint requests and reduces
the number of replica checkpoint requests as compared
to [14].
2.11 Kumar and Khunteta Minimum-Process
Coordinated Check pointing Protocol For Mobile
Distributed System [21]
They designed a minimum process algorithm for mobile
distributed where no useless checkpoint are taken and
an effort has been made to optimize the blocking of
processes. In this algorithm they proposed that during
the checkpoint period, selective message are buffered at
the receiver end. During its blocking period, a process
allowed to perform its normal procedure. So with the
help of this method blocking of process is minimum.
They captured the transitive dependencies during the
normal execution by piggybacking dependency vector
onto computational message. So in this way they try to
reduce the check pointing time by avoiding the
formation of checkpoint tree.
2.12 Kumar and Garg Algorithm[18] : Minimum-
process coordinated check pointing is a suitable
approach to introduce fault tolerance in mobile
distributed systems transparently. It may require
blocking of processes, extra synchronization messages
or taking some useless checkpoints. Checkpointing
overhead may be exceedingly high in all-process
checkpointing. To optimize both matrices, the check
pointing overhead and the loss of computation on
recovery, Kumar and Garg proposed a hybrid
checkpointing algorithm, where an all process
checkpoint is enforced after executing minimum-
process algorithm for a fixed number of time. In the
first phase, the MHs in the minimum set are required to
take soft checkpoint only. Soft Checkpoint is stored on
the disk of the MH and is similar to mutable
checkpoint. In the minimum process algorithm, a
process takes its forced checkpoint only if it is having
a good probability of getting the checkpoint request;
otherwise, it buffers the received messages.
In hybrid checkpointing algorithm all process
coordinated checkpoint is taken after the execution of
minimum-process coordinated check pointing algorithm
for a fixed number of times. The number of useless
checkpoints and blocking of processes are reduced in
minimum-process check pointing. They proposed
probabilistic approach to reduce the number of useless
checkpoints and blocking of process. Thus, the
proposed protocol is simultaneously able to reduce the
useless checkpoints and blocking of processes at very
less cost of maintaining and collecting dependencies
and piggybacking checkpoint sequence numbers onto
normal messages. Concurrent initiations of the
proposed protocol do not cause its concurrent
executions. They try to reduce the loss of
checkpointing effort when any process fails to take its
checkpoint in Coordination with others.
2.13 Ch. D. V. Subba Rao and M.M. Naidu [10]:
Check pointing and message logging are the popular
and general-purpose tools for providing fault-tolerance
in distributed systems. The most of the Coordinated
checkpointing algorithms available in the literature have
not addressed about treatment of the lost messages and
these algorithms suffer from high output commit
latency. To overcome the above limitations, the authors
propose a new coordinated checkpointing protocol
combined with selective sender-based message logging.
The protocol is free from the problem of lost messages.
The term ‘selective’ implies that messages are logged
only within a specified interval known as active
interval, thereby reducing message logging overhead.
All processes take checkpoints at the end of their
respective active intervals forming a consistent global
state. Outside the active interval there is no
checkpointing of process state. This protocol minimizes
different overheads i.e. checkpointing overhead,
message logging overhead, recovery overhead and
blocking overhead. Unlike blocking coordinated
checkpointing, the disk contentions are less in the
proposed protocol. In this protocol there exists
Pinitiator, which coordinates with all the processes to
take a consistent global checkpoint. Pinitiator is
responsible for invoking the checkpoint operation
periodically. It sends control messages, prepare
checkpoint and take checkpoint messages to all other
processes.
2.14 Ajay D. Kshemkalyani [14]:
He proposed a fast and Message-Efficient Global
Snapshot Algorithms for Large-Scale Distributed
Systems. He presented two algorithms: simple tree, and
hypercube, that requires very less number of messages.
In addition, the hypercube algorithm is symmetrical and
has greater potential for balanced workload and
congestion-freedom. This algorithm finds the direct
application in large scale distributation system such as
peer to peer system and MIMD super computer which
are fully connected topology of a large no of processors.
All the algorithms assume non-FIFO channels.
CONCLUSION:
A survey of the literate on checkpointing algorithms for
mobile distributed systems shows that a large number of
papers have been published. We have reviewed and
compared different approaches to checkpointing in
mobile distributed systems with respect to a set of
properties including the assumption of piecewise
determinism, performance overhead, storage overhead,
ease of output commit, ease of garbage collection, ease
of recovery, useless checkpointing, low energy
consumptions.
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